Operating mechanism for artificial hands



A. PRINGLE- AND T. S.KI RK.'

OPERATING MECHANISM FOR ARTIFICIAL HANDS.

APPLICATION. FILED MAR. 28, 1918.,

1,338.1 55. Patented Apr- 27, 1920.

4 SHEETS-SHEET 1.

A. PRINGLE AND T. S. KIRK.

OPERATING MECHANISM, FOR ARTIFICIAL HANDS. APPLICATIQNIILED MAR. 23, 1918.

1 33 155, I Patented Apr. 27, 1920.

4 SHEETS-SHEET 2.

A. PRINGLE AND T. S. KIRK.

OPERATING MECHANISM FOR ARTIFICIAL HANDS.

APPLICATION FILED MAR. 28, 1918.

1,338, 155. Patented Apr. 27, 1920;

KIRK:

APPLICATION FILED MAR. 28, 19l8- b Patented Apr. 27, 1920.

4 SHEETS-SHEET 4.

UNITED s Arias ENT enric OPERATING MEoi-i NIsM For. ARTIFICIAL HANDS.

Specification of Letters Patent. Patented A131. 27, 1920- Ap-p'li'cation filed March 28, 1918. Serial No. 225,147.

To all whom it may concern:

Be it known that we. ALEXANDER and TrIonAs SINCLAIR KIRK, both sul'ijects oi' the King of Great Britain and Ireland, and both residing at Belfast, Ireland, have invented certain new and useful Improvements in and Relating to Operating Mechanism for Artificial Hands, of which the following is .a specification.

This invention has for its object to provide improved operating means for artificial hands of the class in which the fingers can be bent by a pull on a cord or equivalent.

Under this invention, the operating mechanism for an artificial hand is adapted to con trol the pressure with which an article may be gripped by the hand, and also to give a greater gripping efl'ect than is possible with H known operating machanisms.

in order to obtain suilicient power to close the hand, with the desired pressure, the mechanism is so arranged, that the required pull on the wire is obtained by ratcheting mechanism adapted to give a number of successive pulls, each of which acts on the hand operating wire, which would be held by suitable means after each pull, so as to obtain the cumulative effect of the succession of pulling movements of the wire. The increase in gripping action may also be obtained by so arranging the mechanism that an increasing leverage is obtained as the hand closes, or by providing mechanism, as above stated, whereby the cumulative effect of more than one operative movement of the body or arm, as the case may be, can be transmitted by the mechanism to the cord pulling gear with, in either case, suitable releasing or escapement mechanism which is ad opted to give a step-by-step release of the gripping action of the hand.

Various forms of mechanism may be de signed to give the above characteristics and we will now describe, and show on the accompanying drawings, some typical examples, by way of illustration.

On the drawings I Figure-1 is a general view showing operating mechanism adapted to give, from several movements of the arm stump, acumulative pulling action on the hand operating cord, and also showing a convenient form of escapement catch.

Fig. 1 is a general view showing similar mechanism but adapted to be operated by elbow movements.

Figs. 2 and are full size elevation and plan views of mechanism similar to that shown in Fig. 1 but adapted to be located in the small of the back and to be operated by shoulder movements.

Figs. iand 5 are, respectively, a full size back elevation and aside elevation of another mechanism adapted to give cumulative pulling action from several movements of the shoulder. In this case also the mechanism is located in the small of the'back.

Fig. 6 is a view showing an alternative arrangement of operating levers with-an automatic latch.

Fig. 7 shows a joint locking arrangement applicable to artificial hands, operated in accordance with this invention.

Referring to the drawings In the example shown at Fig. 1 the mechanism is designed to give the cumulative pulling action on the hand operating wire or cord in accordance with our invention. The hand operating wire 15 is connected with a lever arm 4. on which a toothed rack '1 is slidably supported in guides 2 and 3 secured to the rack 1 and working over the lever 4. The lever arm 4 is turnably connectedat to a shoulder pad 6 and is secured to a leather cuff or sleeve 8 fitted on the upper arm and to a part 7 of the shoulder pad 6 which carries a catch 7 held in engagement with the teeth of the rack 1 by a spring 9. The catch 7 is adapted, when the rack 1 is moved toward it by inward movements of the lever 4, to engage the teeth of the rack and effect a downward movement thereof at each inward movement of the lever. The catch T is held by the spring 9 against the teeth of the rack until the lever is moved out sufficiently far to cause a pin 7 b on the catch 7 to come into contact with the part 7 of the shoulder pad 6. The catch will then be arrested and will disengage from the teeth of the rack 1 which will then be left under the control of an escapement catch 13 whereby it can be released by a step-by-step movement. as required. The

step-by-step release movement of the rack may be obtained by astill further outward movement of the lever arm 4 by which the catch 13 is rocked on its pivot 13 so that the tooth 13 is pulled out of engagement with the teeth of the rack 1. The rackthen slips up under the return action of the operating wire until the other tooth 13 of the catch 13 fully engages the teeth of the rack, and when the arm lever 1 moves inward the spring 13 returns the tooth 13 into engagement with the teeth of the rack 1. In the example shown, the rocking movement of the catch 13 is obtained by means of a member 141, which is attached to the catch, and preferably carried by or attached to the shoulder pad. The catch. 13 may, if desired, be controlled by a strap attached to the wearers shoulder, arm, or other part of the body. In the example shown, the shoulder pad 6 is formed with a triangular reinforcement of spring steel members 6 6 and 6 from which a portion 6 extends over the shoulder and connects by a strap 6 with a part 8 connecting the lever member with the leather arm sleeve 8, which part also serves to support the 1" orearm socket (not shown).

The reaction oi the inward push of the lever 1 is taken by the triangular shoulc er frame formed by the members 6, (3", and 6, held in position against the push of the lever by suitable harness.

' The mechanism is shown operating by inward movements of the upper arm but it could be arranged to operate by outward movements by reversi r the lever and rack.

In the example shown in Fig. 1 the mechanism is similar to that shown in connection with Fig. 1 but it is operated by elbow move? ments. This mechanism may be attached to a whole arm, and arranged, either on the inner side or the outer thereof, or it may be attached to a crippled arm.

As illustrated, the hand operating wire 15 is connected with a lever arm l secured in place on the arm of the wearer by means of spring clips or straps or equivalent i On the lever arm 4% the toothed rack '1 operates, working over said lever arm. he lever arm a is pivotally connected to another lever arm 41 which. is litted to the lower arm oi? the wea also by means of spring clips or straps or equivalent 1. The catch 7 pivoted to the lever arm l, being i ll in engagement with the teeth of" the ree bv the spring 9, so that when the lever arm el is moved by the movement oi the l r-.ve.' arm, through the elbow joint, the teeth of the rack engage with the catch 7 and an upward movement of the rack 1 is reflected at each movement 01" the lever arm The ratc eting' of the rack upward eli'e ts a cumulative pushfon the outer memberoi the Bowden wire 15 which. outer meml'ier butts against the upper end of the raclr 1 while the wire 15 is secured to the lever arm of the rack until the lever arm 41 is moved sufiiciently by the movement of the lower arm through the elbow joint to cause the catch to disengage from the teeth of the rack which will then be left under the control of the c-scapement catch 13 whereby it can be released by a step-by-step movement, as re- The catch 4' 1s held by the sprmg 9 against the teeth quired. The step-by-step release movement of the rack is obtained by the further movement of the lever arm- 1 through the medium of the control strap or its equivalent 1 which is secured to the lever arm 1 and the catch 13. lVhen this further outward movement takes place the catch 13 is rocked on its pivot 13 so-that the tooth 13 is pulled out of engagement with the teeth of the rack 1. The rack then slips down under the return action of the operating wire until the other tooth 13 of the catch 13 fully engages the teeth of the rack, and when the lever arm 1" is again moved the spring 13 returns the tooth 13 into engagement with the teeth of the rack 1. As already mentioned, the rocking movement of the catch 13, is obtained by means of the control strap or its equivalent 1 which is attached to the catch 13 and lever arm 1*.

In order to put the catch C out of operation, when desired, a pivoted lever i is provided on the lever arm 1* and this lever is connected by a link or its equivalent -1 with the catch 7 By using the pivoted. lever 1 to put the catch 7 out of operation, when desired, greater freedom 0t bending at the elbow is obtained.

A similar mechanism to that shown in Fig. 1? might be adapted for operation by knee or ankle or other body movements.

In the example shown in Figs. 2 and 3 the mechanism is practically thesame that described with reference to Fig. 1, but in this case, the mechanism is located in the small of the back and arranged on a back pad 19 secured to the body by a belt 20. The mechanism is operated by shoulder straps 21 and 22 and the rack is arranged to pull,

by successive pulls on the straps 21, to effect the necessary cumulative action of the rash 1. The catch 7 is operated in a similar manner to the corresponding member shown and described with reference to Fig. 1, but the escapement catch receives its rocking action in the following manner. A. pull on the strap 22, when. unopposed by a pull on-the strap 21, will cause a turning movement of the lever arm 4 about the point 5 and this will cause the catch 13, which is connected to the strap 17 secured to the back pad 19, to be rocked so as to take its tooth 13 out of engagement with the teeth of the rack 1 in the manner previously described.

In the examples illustrated at Figs. 4: and 5, operating); mechanism is shown which is designed to give a cumulative pulling effect with increased leverage as the hand closes. The mechanism in this case is designed to be operated by the shoulder movements and to be located in the small of the back. The mechanism consists of a plate 2 1 on which a lever 25 is turnably connected at 26, said lever having a spring pawl 27 which can operate on and turn a toothed segmentQS to which is secured an eccentric grooved segment 29 to the end 30 of which the hand operating wire is secured. Successive movements of the lever 25, effected by the shoulder strap 31, will cause the pawl 27 to turn the toothed segment 28 and also the eccentric segment 29 whereby the cumulative efl'ect oi": a number of shoulder move ments can be used to exert an increasing pull on the hand operating wire 15. After each positive movement of the lever it is returned. to its starting position by the spring 32, and the toothed segment 28 is retained in its new position by a spring catch 33 which is capable of being released when required, by a pull on the strap 34 which can be actuated from either of the wearers arms or el ewhere. The operating pawl 2'? is, at such times, taken out of en- 'agement with the teeth of the segment 28 by a continuation of the return movement of the lever 25, when the end 27 of the pawl comes into contact-with a'stopper 27 on the plate 2%, so that the pawl is moved clear of the segment teeth. In order to {)IGVQII'C the toothed segment 28 springing back too quickly, under the pull of the hand operating wire or cord, when the holding catch 33 is withdrawn,,we provide a brake member 35 with a friction pad 35 (Fig. 5) between it and the segment 29, turnably carried on the screw threaded spindle 36, which brake member, when turned in the direction of the arrow $23, under the pull of the spring 3?, automatically exerts a braking action on the segment 28. The segment 28 also provided with a friction pad 28 arranged between it and the plate 24, so

that the hand can only be opened slowly. The brake member 35 is controlled by a strap 38 whereby it can be released when it is desired to allow a quick return of the segment 28 to give a greater opening of the hand. The brake member 35 may also be used to give a step-by-step release ofthe grip ii desired. The eccentric segment 29 gives an increasing leverage by taking the pulling point on the hand operating wire closer to the center of the toothed segment 28 as the hand closes.

Bit Fig. 6 we have shown an alternative arrangement of operating levers with an automatic latch. In this case a member 51, provided with a pad (not shown) for bearing against the body, has secured thereto a circular plate 52 on which a disk 53 is turnably supported on a central pivot 54-. At its underside the disk 53 has a segmental toothed rack 55 concentric with the pivot or center of the disk, and on the plate 52 we pivotally secure a spring pawl 56 adapted to engage with the' teeth of the ratchet 55, and having an extension 57, capable of being engaged by the lever 58 at certain positions of said lever. The lever 58 is pivotally carried by or connected with the central pivot 5 1 and is connected with the upper arm by a pad or other suitable means and it projects through a slot 59 left between the plate 52 and the disk 53. The

slot 59 is of such length as to permit of the desired amount oi movement of the disk 53 relative to the plate 52, the end of the operating wire 15 being secured to the disks and 60 and passing through a guide 61 on the member 51.

Movements of the lever 58, effected by inward movements of the upper arm, will cause said lever to engage the edge 62 of the disk 53 and will turn the same in the direction of the arrow :0 thereby causing a pull on 'the wire 15 with the result already described. This turning movement of the lever and disk causes the tooth of the spring pawl 56 to ride over the ratchet 55 so that the pawl ,will maintain the pull at any degree of inward movement of the lever 58 and thereby maintain the grip. The lever 58 can be moved outward, within certain limits, without effecting the release of the grip, but it the lever 58 is moved out far enough to come into contact with the extension 57 of the pawl 56, and if its outward movement is continued, the tooth of the pawl 56 will be moved clear of the ratchet 55 and the disk 53 will then be free, the fingers of the hand being free to release their grip, under their spring action, in the manneralready described.

After completing the movement of the disk 53 by engagement of the lever 58 with the edge 62, as described, it is possible to obtain yet a further movement of the disk, in the same direction, by bringing the lever 58 back and causing the spring catch 58 to engage the notch 62 whereupon by moving the lever again in the direction of the arrow a the disk 58 will be moved to exert a greater pull on the wire 15. lVhen the lever 58 is moved back to release the grip, the spring catch 58 is held out of action by the projection 52 on the plate 52.

An example 01" a joint locking arrangement is shown at Fig. 7 where the wrist joint is of ball and socket type. A Bowden wire is used as the hand operating cable. The outer casing bears against one part 84: of the joint while the other part 83 of the oint is pulled up by the operating or inner wire 15 and against the first mentioned portion 84 and locked to, or against, same by said pull or pressure. In order to insure that the operating cable will be straight at, or through, the joint, a flanged bush 85 is provided, slidable in the part 84; of thejoint and capable of clamping the part 84 to the other part 83. The clamping arrangement may, in some cases, comprise in the one part of the joint a locking bolt slidably supported and capable of being operated by the wire to engage the other part of the joint, so as to lock the parts when the wire is under tension, and which will be unlocked when the pull on the wire is relieved. It is to be understood that this feature is not confined to ball and socket but applies to all classes of wrist or arm joints.

Having now fully described our lnvention, what we claim and desire to secure by Letters Patent is 1. Operating mechanism ior artificial hands having means for bending the fingers of the hand, comprising ratcheting mechanism operating in conjunction with the fin gers, means in connection with the ratcheting mechanism for effecting a plurality of gers, means in connection with the ratcheting mechanism for effecting a plurality of movements of same, means whereby the cumulative effect of the plurality of movements is transmitted to the hand to close same and means adapted to give a step-bystep release of the gripping action of the hand.

3. Operating mechanism for artificial hands having means for bending the fingers of the hand, comprising lever mechanism, a toothed rack working in conjunction with the lever mechanism, guides for supporting the rack, means for supporting the lever mechanism on the body of the wearer and rocking pawl and spring mechanism in conjunction with the rack for moving same to operate the finger bending means.

4:. Operating mechanism for artificial hands having means for bending the fingers of the hand, comprising lever mechanism, a toothed rack working in conjunction with the lever mechanism, guides for supporting the rack, means for supporting-the lever mechanism on the body of the wearer and means in conjunction with the rack for effecting a cumulative action thereof to operatethe finger bending means.

5. Operating mechanism for artificial hands having means for bending the fingers of the hand, comprising lever mechanism, a toothed rack working in conjunction with the lever mechanism, guides for supporting the rack, means for supporting the lever mechanism on the body of the wearer and rocking pawl and spring mechanism in conjunction with the rack for effecting a cumulative action thereof to operate the finger bending means.

6. Operating mechanism for artificial hands having means for bending the fingers of the hand, comprising lever mechanism, a

toothed rack working in conjunction with the lever mechanism, guides for supporting the rack, means for supporting the lever mechanism on the body of the wearer, rocking pawl and spring mechanism in conjunction with the rack to operate the finger bending mechanism and means for giving a step-by-step release to the finger bending mechanism.

7. Operating mechanism for artificial hands having means for bending the fingers of the hand, comprising lever mechanism, a toothed rack working in conjunction with the lever mechanism, guides for supporting the rack, means for supporting the lever mechanism on the body of the wearer, rocking pawl and spring mechanism in conjunction with the rack to operate the finger bending mechanism, an automatic latch for regulating the grip of the fingers and a brake member for giving a step-by-step release to the finger bending mechanism.

In testimony whereof we aflix our signatures in presence of two witnesses.

ALEXANDER PRINGLE. THOMAS SINCLAIR KIRK.

Witnesses:

ANDREW HAMILTON, JOHN KNOX. 

